1. Field of the Invention
The present invention relates to a method, particularly to a method for making an interdental brush.
2. Description of the Related Art
FIG. 1 show “A Method for Making an Interdental Brush” issued by a Japan publication No. 10-155546. The conventional interdental brush 1 comprises a handle 11, a bristle stem 12 connected to the handle 11, and a filler 13 for wrapping the handle 11 up. Wherein, the handle 11 includes a handle body 111, a plurality of apertures 112 respectively defined on the handle body 111 at intervals, and a through hole 113 placed on one end of the handle body 111 and intercommunicated with the apertures 112. In manufacturing, one end of the bristle stem 12 is inserted into the through hole 113, and thence rods 14 are put in the apertures 112 for propelling the bristle stem 12 inside the through hole 113 so as to form a bent portion 121 with a bending angle α on the bristle stem 12. Finally, the filler 13 is able to fill the through hole 113 and the apertures 112, and the completion of the interdental brush 1 is achieved.
However, although the bristle stem 12 is propelled by the rods 14 to form bent portions thereon, the bent portions of the bristle stem 12 do not clasp any engaging portion. As a result, even if the bristle stem 12 is wrapped in the filler 13, a slight pulling force is able to pull the bristle stem 12 out, thus incurring an unstable engagement between the bristle stem 12 and the handle 11. Moreover, since the bristle stem 12 is twisted by wires, such formation readily brings on the resilience after the propelling. Namely, even if a certain bent portion is formed while the bristle stem 12 is thrust, the resilience generated therefrom still lessening the bending angle α of the bristle stem 12. Therefore, the engagement between the bristle stem 12 and the handle 11 is influenced and an improvement is needed.
In order to remove abovementioned shortcomings, another method for making an interdental brush issued by an EP patent application no. 1625808A1 is shown in FIG. 2. The interdental brush 2 comprises a handle 21, a bristle stem 22 connected to the handle 21, and a filler 23 for wrapping the handle 21 up. Wherein, the handle 21 includes a handle body 211, two fixing slots 212 defined on the handle body 211 at intervals and communicated with the exterior, a through hole 213 positioned on the handle body 211 and intercommunicated with the fixing slots 212, and a fixing hole 214 placed on the handle body 211 and correspondent with the fixing slots 212. In manufacturing, the bristle stem 22 is sequentially inserted into the through hole 213 until being fixed into the fixing hole 214. Thereafter, a rod 24 is employed to shove the bristle stem 22 in one of the fixing slots 212 for generating a bent portion 221 on the bristle stem 22, so that the bent portion 221 would be able to engage with the fixing slot 212. Lastly, the filler 23 is applied to wrap the fixing slot 212 up for achieving a finished interdental brush 2.
However, in using, even if the bent portion 221 is able to engage with the fixing slot 212 for increasing a firm combining effect between the bristle stem 22 and the handle 21, the resilience on the bristle stem 21 still exists after removing the shoving force from the rod 24. Namely, while taking away the shoving from the rod 24, the bending angle of the bent portion 221 is too slight to firmly engage with the fixing slot 212. As a result, the combining effect between the bristle stem 21 and the handle 21 is influenced and awaiting an improvement.
Another interdental brush issued by a JP patent application no. 2009-247531 is shown in FIG. 3. The interdental brush 3 comprises a handle 31, a bristle stem 32 connected to the handle 31, and a filler 33 for wrapping the handle 31 up. Wherein, the handle 31 includes a through hole 311 defined thereon and a plurality of fixing slots 312. Moreover, the fixing slots 312 are not intercommunicated with the through hole 311; namely, an encompassing portion 313 is formed around the exterior of the through hole 311. Thereby, after inserting the bristle stem 32 into the through hole 311, an extruding device is employed to extrude the encompassing portion 313 from the fixing slots 312 so as to correspondingly extrude and fix the bristle stem 32. Consequently, the fixing slots 312 would be wrapped in the filler 33 for achieving the finished interdental brush 3. However, in such extruding manner, the encompassing portion 313 adopts the plastic material that is characterized by a higher plasticity, and the bristle stem 32 adopts the metal material that possesses a lower malleability. Accordingly, when the encompassing portion 313 is extruded, the bristle stem 32 would not be efficiently deformed by the coming encompassing portion 313. Instead, the bristle stem 32 is subjected to sink in the encompassing portion 313. Further, since the fixing slots 312 are not intercommunicated with the through hole 311, the stem 32 is incapable of being wrapped well while the filler 33 is applied. Therefore, during the using, the bristle stem 32 readily departs from the handle 31 in view of any accidental external pulling and dragging. Thus, an improvement is still needed.